The sun starts to rise behind Britain's largest offshore wind farm off the Great Yarmouth coastline in Norfolk, England.Matt Cardy/Getty Images

Offshore wind developers and national environmental groups have agreed on a plan to protect one of the world’s most endangered species.

The companies will observe stricter rules to protect the North Atlantic right whale, which regularly migrates south along the Atlantic coast.

"Offshore wind energy is a critical component to our nation’s long-term energy security," said Jeff Grybowski, CEO of Deepwater Wind, a developer involved in a project 23 miles off the coast of Atlantic City. "But this energy resource must be developed responsibly."

The agreement "helps ensure these Atlantic offshore wind industry leaders can develop while protecting critically endangered right whales," said Justin Allegro of the National Wildlife Federation. Limiting work during certain seasons, slowing down boats, reducing sound disturbances in the ocean, and having spotters look for whales are part of agreed-upon mitigation measures.

The North Atlantic right whale is one of the most endangered species in the world. Only 350 to 400 are left and even the loss of a single female could affect the species’ long-term viability, according to the National Marine Fisheries Service. The pregnant whales travel from the New England coast south to waters off Georgia and Florida in the winter. Because they swim near the surface, many have been killed by large ships, Allegro added.

Also participating in the agreement are the Conservation Law Foundation, the Sierra Club and the National Resources Defense Council.

The agreement covers only preliminary assessments of offshore sites. Construction and operations will be subject to a separate federal review and permitting process.

New Jersey still has not started its offshore wind program in earnest, though two different companies have placed buoys off the coast to collect data for possible sites.